package com.baomidou.kisso.common.bcprov.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Vector;

public final class Strings {

	public static String fromUTF8ByteArray( byte[] bytes ) {
		int i = 0;
		int length = 0;

		while ( i < bytes.length ) {
			length++;
			if ( (bytes[i] & 0xf0) == 0xf0 ) {
				// surrogate pair
				length++;
				i += 4;
			} else if ( (bytes[i] & 0xe0) == 0xe0 ) {
				i += 3;
			} else if ( (bytes[i] & 0xc0) == 0xc0 ) {
				i += 2;
			} else {
				i += 1;
			}
		}

		char[] cs = new char[length];

		i = 0;
		length = 0;

		while ( i < bytes.length ) {
			char ch;

			if ( (bytes[i] & 0xf0) == 0xf0 ) {
				int codePoint = ((bytes[i] & 0x03) << 18)
						| ((bytes[i + 1] & 0x3F) << 12) | ((bytes[i + 2] & 0x3F) << 6) | (bytes[i + 3] & 0x3F);
				int U = codePoint - 0x10000;
				char W1 = (char) (0xD800 | (U >> 10));
				char W2 = (char) (0xDC00 | (U & 0x3FF));
				cs[length++] = W1;
				ch = W2;
				i += 4;
			} else if ( (bytes[i] & 0xe0) == 0xe0 ) {
				ch = (char) (((bytes[i] & 0x0f) << 12) | ((bytes[i + 1] & 0x3f) << 6) | (bytes[i + 2] & 0x3f));
				i += 3;
			} else if ( (bytes[i] & 0xd0) == 0xd0 ) {
				ch = (char) (((bytes[i] & 0x1f) << 6) | (bytes[i + 1] & 0x3f));
				i += 2;
			} else if ( (bytes[i] & 0xc0) == 0xc0 ) {
				ch = (char) (((bytes[i] & 0x1f) << 6) | (bytes[i + 1] & 0x3f));
				i += 2;
			} else {
				ch = (char) (bytes[i] & 0xff);
				i += 1;
			}

			cs[length++] = ch;
		}

		return new String(cs);
	}


	public static byte[] toUTF8ByteArray( String string ) {
		return toUTF8ByteArray(string.toCharArray());
	}


	public static byte[] toUTF8ByteArray( char[] string ) {
		ByteArrayOutputStream bOut = new ByteArrayOutputStream();

		try {
			toUTF8ByteArray(string, bOut);
		} catch ( IOException e ) {
			throw new IllegalStateException("cannot encode string to byte array!");
		}

		return bOut.toByteArray();
	}


	public static void toUTF8ByteArray( char[] string, OutputStream sOut ) throws IOException {
		char[] c = string;
		int i = 0;

		while ( i < c.length ) {
			char ch = c[i];

			if ( ch < 0x0080 ) {
				sOut.write(ch);
			} else if ( ch < 0x0800 ) {
				sOut.write(0xc0 | (ch >> 6));
				sOut.write(0x80 | (ch & 0x3f));
			}
			// surrogate pair
			else if ( ch >= 0xD800 && ch <= 0xDFFF ) {
				// in error - can only happen, if the Java String class has a
				// bug.
				if ( i + 1 >= c.length ) {
					throw new IllegalStateException("invalid UTF-16 codepoint");
				}
				char W1 = ch;
				ch = c[++i];
				char W2 = ch;
				// in error - can only happen, if the Java String class has a
				// bug.
				if ( W1 > 0xDBFF ) {
					throw new IllegalStateException("invalid UTF-16 codepoint");
				}
				int codePoint = (((W1 & 0x03FF) << 10) | (W2 & 0x03FF)) + 0x10000;
				sOut.write(0xf0 | (codePoint >> 18));
				sOut.write(0x80 | ((codePoint >> 12) & 0x3F));
				sOut.write(0x80 | ((codePoint >> 6) & 0x3F));
				sOut.write(0x80 | (codePoint & 0x3F));
			} else {
				sOut.write(0xe0 | (ch >> 12));
				sOut.write(0x80 | ((ch >> 6) & 0x3F));
				sOut.write(0x80 | (ch & 0x3F));
			}

			i++;
		}
	}


	/**
	 * A locale independent version of toUpperCase.
	 * 
	 * @param string input to be converted
	 * @return a US Ascii uppercase version
	 */
	public static String toUpperCase( String string ) {
		boolean changed = false;
		char[] chars = string.toCharArray();

		for ( int i = 0 ; i != chars.length ; i++ ) {
			char ch = chars[i];
			if ( 'a' <= ch && 'z' >= ch ) {
				changed = true;
				chars[i] = (char) (ch - 'a' + 'A');
			}
		}

		if ( changed ) {
			return new String(chars);
		}

		return string;
	}


	/**
	 * A locale independent version of toLowerCase.
	 * 
	 * @param string input to be converted
	 * @return a US ASCII lowercase version
	 */
	public static String toLowerCase( String string ) {
		boolean changed = false;
		char[] chars = string.toCharArray();

		for ( int i = 0 ; i != chars.length ; i++ ) {
			char ch = chars[i];
			if ( 'A' <= ch && 'Z' >= ch ) {
				changed = true;
				chars[i] = (char) (ch - 'A' + 'a');
			}
		}

		if ( changed ) {
			return new String(chars);
		}

		return string;
	}


	public static byte[] toByteArray( char[] chars ) {
		byte[] bytes = new byte[chars.length];

		for ( int i = 0 ; i != bytes.length ; i++ ) {
			bytes[i] = (byte) chars[i];
		}

		return bytes;
	}


	public static byte[] toByteArray( String string ) {
		byte[] bytes = new byte[string.length()];

		for ( int i = 0 ; i != bytes.length ; i++ ) {
			char ch = string.charAt(i);

			bytes[i] = (byte) ch;
		}

		return bytes;
	}


	/**
	 * Convert an array of 8 bit characters into a string.
	 *
	 * @param bytes 8 bit characters.
	 * @return resulting String.
	 */
	public static String fromByteArray( byte[] bytes ) {
		return new String(asCharArray(bytes));
	}


	/**
	 * Do a simple conversion of an array of 8 bit characters into a string.
	 *
	 * @param bytes 8 bit characters.
	 * @return resulting String.
	 */
	public static char[] asCharArray( byte[] bytes ) {
		char[] chars = new char[bytes.length];

		for ( int i = 0 ; i != chars.length ; i++ ) {
			chars[i] = (char) (bytes[i] & 0xff);
		}

		return chars;
	}


	public static String[] split( String input, char delimiter ) {
		Vector v = new Vector();
		boolean moreTokens = true;
		String subString;

		while ( moreTokens ) {
			int tokenLocation = input.indexOf(delimiter);
			if ( tokenLocation > 0 ) {
				subString = input.substring(0, tokenLocation);
				v.addElement(subString);
				input = input.substring(tokenLocation + 1);
			} else {
				moreTokens = false;
				v.addElement(input);
			}
		}

		String[] res = new String[v.size()];

		for ( int i = 0 ; i != res.length ; i++ ) {
			res[i] = (String) v.elementAt(i);
		}
		return res;
	}
}
